The Vacuum Deal

[wxman1]

Greetings All:

I'm running a 69 C10 Pickup with a 350CID
engine that uses a 600cfm Holley 4 barrel.
I'm posting a link to a pic of the engine below:

http://mywebpages.comcast.net/wxgeek/holley_600cfm.jpg

Ok, here's the question. When I disconnect the
vacuum advance line from the distributor
I see NO change in the timing mark for number one
cylinder. The line is connected per Holleys
instructions to the Vacuum Advance Port. The port
below is the full manifold vacuum port that the
modulator for the transmission (TH350) is
connected to.

So whats the deal...Is the vacuum advance can
bad or what?

Engine timing at idle with the vacuum advance line
disconnected is around 11 deg BTDC.

Jim M.
Mt Juliet TN